I'd be interested in finding the original sources for these studies. Interesting stuff, but of course I have lots of questions... while I do think people differ in terms of how organized or spontaneous or emotional they are, I'm often disturbed when it's framed in terms of "left" and "right" brain. I'm pretty certain if we asked a neuroscientist they would tell us the brain doesn't really work in such stark left/right fashion.
And I wonder how the 2 studies fit together. It would seem the people from the first study who were the most successful (the controlled, methodical, sticklers from group "B") are NOT like the successful people from the second study who were open to dramatic changes in their lives. They sound more like "D" people...
Finally, getting more at the categories they discuss from the first study, you could probably guess from the above that I am probably more "A" than anything else
Though not with regard to "working with machinery"...